Case study 3: Germany: Crop diversification to improve water quality in catchment basin

Cluster 1: Service crops

In Lower Saxony nitrogen concentration increases in groundwater amongst others due to high stocking rates and to the development of a biogas production unit. This area is characterized by a diversity of farming systems ranging from specialized livestock production to specialized cropping systems with also mixed farms. The challenge is to maintain drinking water quality through the adaptation of farmer practices in water protection areas.

What are the main problems underlying the emergence of the case study?
The challenge, highlighted by water suppliers, is to maintain drinking water quality through the adaptation of farmer practices in water protection areas. In this area of Lower Saxony, N concentration increases in groundwater amongst others due to high stocking rates and to the development of a biogas production unit. This area is characterized by a diversity of farming systems, ranging from specialized livestock production to specialized cropping systems with also mixed farms.
This problem, firstly focused on nitrate content in drinking water, is currently extended to the problem of pesticide content in water and on ground water quality outside of water protection areas.

How is the problem addressed and which actors are involved?
At the moment, 350 farmers are under special guidance of the regional office Nienburg (between Hannover and Bremen in the North of Germany) of LWK Niedersachsen.
To take into account the different distances of fields from the well, two zones are defined in the water protection area. The inner zone has stricter rules for fertilization (no slurry) in combination with adjustment, while farming in the outer zone is also under special guidance, but measures for reduced N-leachate (use of cover crops between two maize crops, reduced tillage) are established on a voluntary basis between farmers and advisors/water suppliers. 

Solution investigated
Two schemes are tested in order to reduce the pressure exerted by the agricultural sector on groundwater resources through
1) a measure-based adjustment payment and
2) farmer payment if their farming practice results in defined low N-residues.

Expected outcome
1) Objectify the agrotechnical, economic, and environmental performances of the two introduced schemes in order to preserve biodiversity and minimize nitrogen leachate and economic loss inside and outside of the water protection areas.
2) Define, between the farmers (cropping farms and biogas farms), the win-win contract schemes to support the catch crop shifting toward cash crops. For this, solutions for a possible use of catch crops under green direct payments are needed.

Relevance to the DiverIMPACTS goals
Benefit from international experiences with crop rotations to enhance the performance of water protection and to meet the needs of everyday-farming.

Contact

  • Hauke Ahnemann, LWK Niedersachsen, case study leader
  • Dirk Ehlers, LWK Niedersachsen, cae study monitor